feat: M4 文风 + M5 生成/多provider/Skill + Kimi Code 订阅接入 + 本地联调修复

M4（文风）: style-auditor 双轨（提取指纹/漂移第四审）+ jobs 长任务框架(zombie reaper) + 回炉 refine + GET /style read-back。
M5（生成+扩展）: worldbuilder/character-gen（入库 continuity 409 gate + partition_writes 白名单 + schema→JSONB 形变）；
  网关多 provider 回退链/熔断/能力降级（Anthropic/Gemini 适配器）；Skill registry + 表权限沙箱 + 规则；
  前端 角色生成器/世界观/Codex/规则页/技能库/⌘K 命令面板。
K1（Kimi Code 订阅接入）: OAuth device-flow（kimi-code）+ 静态 Console key（kimi-code-key）两路径；
  coding 端点 KimiCLI 伪造头（实测 UA allow-list 门禁，缺则 403）+ JSON 模式结构化（thinking ⊥ tool_choice）。
本地联调修复: CORS 中间件；assemble 注入 premise+「写第N章」指令（修空 prompt 400）；
  GET /outline·/draft read-back + 大纲/工作台/审稿页重载；写页 client/server 常量边界 + notFound 健壮化；
  字数 toLocaleString locale 水合；审稿页终稿从已存草稿 seed（修 accept 422）。
门禁: backend ruff/mypy(157)/alembic 无漂移/pytest 451 · frontend lint/tsc/vitest/build。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/web/lib/style/useRefine.ts

@@ -0,0 +1,91 @@
+"use client";
+
+import { useCallback, useState } from "react";
+
+import { api } from "@/lib/api/client";
+import { useToast } from "@/components/Toast";
+import type { RefineResponse } from "@/lib/api/types";
+import { buildRefineRequest } from "./style";
+
+export type RefineStatus = "idle" | "refining" | "done" | "error";
+
+export interface RefineResult {
+  original: string;
+  refined: string;
+}
+
+export interface UseRefine {
+  status: RefineStatus;
+  result: RefineResult | null;
+  // 回炉重写某段（可选改写指令）→ 返回 {original, refined} 或 null（失败）。
+  refine: (
+    projectId: string,
+    chapterNo: number,
+    segment: string,
+    instruction?: string,
+  ) => Promise<RefineResult | null>;
+  reset: () => void;
+}
+
+function errorCode(error: unknown): string | undefined {
+  if (typeof error !== "object" || error === null) return undefined;
+  const env = error as { error?: { code?: unknown } };
+  return typeof env.error?.code === "string" ? env.error.code : undefined;
+}
+
+// 回炉（POST .../refine）：同步返回新旧 diff，不写库（不变量#3）。
+// 503 LLM_UNAVAILABLE（无凭据）优雅提示去设置；其余失败 toast。
+export function useRefine(): UseRefine {
+  const [status, setStatus] = useState<RefineStatus>("idle");
+  const [result, setResult] = useState<RefineResult | null>(null);
+  const toast = useToast();
+
+  const refine = useCallback<UseRefine["refine"]>(
+    async (projectId, chapterNo, segment, instruction) => {
+      setStatus("refining");
+      setResult(null);
+      try {
+        const { data, error } = await api.POST(
+          "/projects/{project_id}/chapters/{chapter_no}/refine",
+          {
+            params: {
+              path: { project_id: projectId, chapter_no: chapterNo },
+            },
+            body: buildRefineRequest(segment, instruction),
+          },
+        );
+        if (error || !data) {
+          setStatus("error");
+          const code = errorCode(error);
+          toast(
+            code === "LLM_UNAVAILABLE"
+              ? "未配置提供商，请先去设置页连一家。"
+              : "回炉失败，请稍后重试。",
+            "error",
+          );
+          return null;
+        }
+        const next = data as RefineResponse;
+        const outcome: RefineResult = {
+          original: next.original,
+          refined: next.refined,
+        };
+        setResult(outcome);
+        setStatus("done");
+        return outcome;
+      } catch {
+        setStatus("error");
+        toast("回炉请求异常，请检查网络。", "error");
+        return null;
+      }
+    },
+    [toast],
+  );
+
+  const reset = useCallback((): void => {
+    setStatus("idle");
+    setResult(null);
+  }, []);
+
+  return { status, result, refine, reset };
+}